1. HOT SEAT

2. Question #1
What three general conditions (or assumptions) do you need to check before you perform inference?
Random, Normal, Independent

3. Question #2
What three things should you include in your “STATE” when you are going to perform a significance test?
Hypotheses, significance level, parameter

4. Question #3
How do you check for the Normal condition when a proportion is your parameter of interest?
np and n(1-p) ≥ 10

5. Question #4
You always have to check for independence, but when do you have to check the 10% rule?
When sampling without replacement!

6. Question #5
What are the three things you must include when you are “concluding” a confidence interval?
Confidence level, interval, and the parameter (captures the true population’s…)

7. Question #6
What are the two main calculations in the “DO” part of a significance test?
Test statistic and the P-value

8. Question #7
When checking the Normal condition for an inference method involving mean, you can assume the condition is met if the sample size is large enough – how large does it have to be?
Greater than or equal to 30.

9. Question #8 Choose a following answer:
Which of the following is NOT true about P-values?
It gives us the chances of our sample results given that the null hypothesis is true.
It allows us to make a decision to reject or fail to reject the null hypothesis.
The P stands for the “Power” value
Given what type of test we are using, we can use either Table A, Table B, or the graphing calculator to find this value.

10. Question #9 What is the parameter of interest?
An opinion poll asks a random sample of adults whether they favor banning ownership of handguns by private citizens. A commentator believes that more than half of all adults favor such a ban.
p = proportion of adults who are in favor of the ban

11. Question #10
What type of test would you use for this problem? (give the entire method name)
An opinion poll asks a random sample of adults whether they favor banning ownership of handguns by private citizens. A commentator believes that more than half of all adults favor such a ban.
One sample z test for a population proportion

12. Question #11 What would a Type I error be in this case?
An opinion poll asks a random sample of adults whether they favor banning ownership of handguns by private citizens. A commentator believes that more than half of all adults favor such a ban.
We would reject that half of the adults favor the ban when actually half of the adults do favor the ban.

13. Question #12 The power of a test is .88, what does this mean?
That there is an 88% chance that we will reject the null hypothesis when the null was false.
Alternative answer: That there is a 12% chance of a Type II error

14. Question #13 State the hypotheses for this problem:
Athletes performing in bright sunlight often smear black grease under their eyes to reduce glare. Does eye black work? In one experiment, 16 randomly selected student subjects took a test of sensitivity to contrast after 3 hours facing into bright sun, both with and without eye black. Here are the differences in sensitivity, with eye black minus without eye black:
We want to know whether eye black increases sensitivity on average.
H0: µd = 0 and Ha: µd > 0

15. Question #14 He needs to draw a graph!
Athletes performing in bright sunlight often smear black grease under their eyes to reduce glare. Does eye black work? In one experiment, 16 randomly selected student subjects took a test of sensitivity to contrast after 3 hours facing into bright sun, both with and without eye black. Here are the differences in sensitivity, with eye black minus without eye black:
We want to know whether eye black increases sensitivity on average.
See Cody’s work below, what is he missing when he checked the Normal condition?
Normal: Although the sample size is small (less than 30), I will assume this is roughly Normal because it is unimodal and symmetric.
He needs to draw a graph!

16. Question #15
A random sample of 100 likely voters in a small city produced 59 voters in favor of Newt Gingrich. The observed value of the test statistic for testing the null hypothesis:
H0: p = 0.5 versus the alternative hypothesis Ha: p > 0.5 is
a) b) c)
d) e)

17. Question #16
Given a H0: µ = 0; Ha: µ ≠ 0 and from data has a and with a sample size of 18.
Assuming that the conditions are met, Sara calculated the test statistic and used
her calculator function tcdf(1.20, 100, 17) = Why is her P-value not 12.3%?
- Because she needs to double .123 to become 0.247!

18. Question #17 Name three ways to increase the power of a test.
Increase α, decrease β, increase sample size